tests/safe-signal-output-removal: Add test for output removal

This simulates an output removal which should trigger a crash when
the compositor is shutdown abruptly by having a view with a listener installed
on its output_destroy signal.

This patch assumes that weston_compositor_remove_output() has already
been amended to use the more safer version for triggering signal
emission.

As both shells use this construct it should catch any potential signal
corruption.

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>

tests/meson.build

@@ -217,6 +217,13 @@ tests = [
 		],
 	},
 	{	'name': 'safe-signal', },
+	{	'name': 'safe-signal-output-removal',
+		'sources': [
+		  'safe-signal-output-removal-test.c',
+		  '../shared/shell-utils.c',
+		],
+		'dep_objs': [ dep_lib_desktop ]
+	},
 ]
 
 tests_standalone = [

tests/safe-signal-output-removal-test.c

@@ -0,0 +1,133 @@
+/*
+ * Copyright 2021 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include "config.h"
+
+#include <unistd.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "../shared/signal.h"
+#include "../shared/shell-utils.h"
+#include "weston-test-client-helper.h"
+#include "weston-test-fixture-compositor.h"
+
+struct test_output {
+       struct weston_compositor *compositor;
+       struct weston_output *output;
+       struct wl_listener output_destroy_listener;
+       struct weston_view *view;
+};
+
+static enum test_result_code
+fixture_setup(struct weston_test_harness *harness)
+{
+       struct compositor_setup setup;
+
+       compositor_setup_defaults(&setup);
+       setup.shell = SHELL_TEST_DESKTOP;
+
+       return weston_test_harness_execute_as_plugin(harness, &setup);
+}
+
+DECLARE_FIXTURE_SETUP(fixture_setup);
+
+static void
+output_destroy(struct test_output *t_output)
+{
+       t_output->output = NULL;
+       t_output->output_destroy_listener.notify = NULL;
+
+       if (t_output->view)
+               weston_surface_destroy(t_output->view->surface);
+
+       wl_list_remove(&t_output->output_destroy_listener.link);
+       free(t_output);
+}
+
+static void
+notify_output_destroy(struct wl_listener *listener, void *data)
+{
+       struct test_output *t_output =
+               container_of(listener, struct test_output, output_destroy_listener);
+
+       output_destroy(t_output);
+}
+
+static void
+output_create_view(struct test_output *t_output)
+{
+       struct weston_solid_color_surface solid_surface = {};
+
+       solid_surface.r = 0.5;
+       solid_surface.g = 0.5;
+       solid_surface.b = 0.5;
+
+       solid_surface.get_label = NULL;
+       solid_surface.surface_committed = NULL;
+       solid_surface.surface_private = NULL;
+
+       t_output->view =
+               create_solid_color_surface(t_output->compositor,
+                                          &solid_surface, 0, 0, 320, 240);
+       weston_view_set_output(t_output->view, t_output->output);
+
+       /* weston_compositor_remove_output() has to be patched with
+	* weston_signal_emit_mutable() to avoid signal corruption */
+       weston_output_destroy(t_output->output);
+}
+
+static void
+output_create(struct weston_output *output)
+{
+       struct test_output *t_output;
+
+       t_output = zalloc(sizeof *t_output);
+       if (t_output == NULL)
+               return;
+
+       t_output->output = output;
+       t_output->compositor = output->compositor;
+
+       t_output->output_destroy_listener.notify = notify_output_destroy;
+       wl_signal_add(&t_output->output->destroy_signal,
+                     &t_output->output_destroy_listener);
+
+       output_create_view(t_output);
+}
+
+static void
+create_outputs(struct weston_compositor *compositor)
+{
+       struct weston_output *output, *output_next;
+
+       wl_list_for_each_safe(output, output_next, &compositor->output_list, link)
+               output_create(output);
+}
+
+PLUGIN_TEST(real_usecase_one)
+{
+       create_outputs(compositor);
+}